Nurikabe is a puzzle game that's kinda like the Asian board game "Go". How do you play it? Well, it's kind of complicated, but not to worry since there's a tutorial for it. Essentially you have a grid with some squares with a number in it. Those squares must have exactly that many white squares connected to it including itself. These white areas cannot be connected to other white areas. The rest of the grid must be covered with black squares. Now there's some rules for the black squares. You can not have a black area that's 2x2 or larger and the black areas MUST be fully connected. If you think you got it but aren't sure, try the beginner's problems. If you think you've got it try the sample problems. They also have a guide if you need further help.

The game is a java applet so you need a java enabled browser and also if you leave the page, the applet window will disappear.

There's some other interesting games on that site though, so check them out.